Whiter than Whitehttp://www.randelljohnphotography.com/high-key-lighting/
I was surfing the net this evening and I somehow ended up on one Tony Northrup’s YouTube video’s
Apparently Tony only uses a flash meter when he’s using film. Each to their own, but to achieve consistent and predictable results, then I firmly believe that actually measuring the light in a scene is the only way to go.
First of all lets just get some terminology correct.
Just because you have a white backdrop, doesn’t make for a ‘High Key Photograph’.
A high key photograph is one in which tones lighter than mid grey to white, are predominant features within the frame.
Having a head and shoulders shot of someone with raven black hair and a pink pullover is not a ‘High Key Portrait’. Although Tony and Chelsea are only demonstrating light placement and power settings in the video, I think this video could cause some confusion as to what constitutes high key photography in the true sense of the term.
O.K so I’ve got that little explanation out-of-the-way, I’ll move on.
We’ve been bombarded with poor high key photography over the years, so much so that it’s become almost impossible for the general public to tell the difference between a well crafted high key image, and the usual chaff we see from some of those large ‘pack em in hard sell studio’s’.
But just to make things clear, blasting light at a backdrop until the ‘Blinkies’ on the camera’s LCD illuminate isn’t the correct way to set up a white backdrop.
The digital sensor of a DSLR is very vulnerable to blown highlights.
The ‘Blinkies’ or ‘Highlight Warnings’ are the camera’s method of telling the photographer that our whites in the scene are over exposed, (personally I hate this warning and turn it off as I find it very distracting).
If we take this badly exposed image into Photoshop and use the eye-dropper tool, and sample the exposure on this backdrop, we can easily see that the RGB information will read 255, 255, 255 (Pure White).
Great you may think, I’ve used one or two strobes and made a pure white high key backdrop without the need to touch up the scene in post processing.
Well yes and no. The whites may look white on your monitor – but……
Remember photography is a printed medium, it isn’t video. Our digital images are supposed to be printed, and preferably mounted and framed, if we are to consider our work complete.
The problem with the RGB 255, 255, 255 scenario, is that if we print our file using an ink jet or laser printer, then the whole over exposed area will lack any ink on the print.
Modern inkjet and even more expensive laser printers use a subtractive system of producing colour.
Pure white would give an ink usage code of Cyan = 0, Magenta = 0, Yellow = 0, Key = 0 (i.e zero amount of ink used), leaving the colour of the paper to dictate the white point, (Bearing in mind not all photographic papers are equal, and that some are more blue others a warmer yellow depending on the amount of bleach used in their manufacture), then this really negates the effort of trying to achieve a pure white backdrop in the first place.
If we are to create and sell high quality printed images for our customers, then I think it only fair that we only consider selling a photograph that is covered in ink, and not include huge swathes of inkless desert, where we have lost control of the printing process.
The fastest and easiest way to get a white high key backdrop that will actually print correctly is to use a flash meter.
As long as the background is exposed as close to pure white, but is of a tonal value below the dreaded 255,255,255 RGB limit, then we will produce a correctly exposed image, that will print correctly and look great.
I will normally correctly expose my background 1.3 stops above my key light, making sure that I get an even spread of light on the part of the backdrop I’m photographing. (This may be different for you and totally depends on the dynamic range of your camera’s sensor, but for my 5D MkII’s it works very well).
In addition to this, a quick check with my meter pointed towards the backdrop measured from the back of my models head, will ideally give me a reading of at least 1.3 stops lower than my exposure on the background (i.e equal to the key light and preferably below this reading).
If the measurement is higher than this, then there’s a definite risk that my image will lose contrast, as the light reflecting from the backdrop, will begin to expose and ‘wrap’ around my model. In other words my backlight could spill over onto the models face and destroy my key exposure .
Although this washed out look is sometimes used for effect in fashion photography, it has no place in traditional portraiture, and even less so in wedding photography where it’s paramount that we record the details in a brides dress, without blowing out the whites.
To correct this fault, then either lower the output of the strobes lighting the backdrop or, preferably, if you have enough room, move your subject further away from the backdrop.
In conclusion, to produce consistent and professional high key portraits, then we all need to know how to light a white backdrop correctly.
Use a flash meter. Your LCD can only tell you how much total light you have in the scene, it won’t tell you where that light is coming from or how it’s distributed.
The Blinkies only tell us, that the scene is overexposed.
Use the tools of the trade, and learn how to create quality prints that have real value for you customers, and leave the guess-work to the amateurs and those that just don’t care about the work they produce and sell.
And always keep in mind that it isn’t a photograph until it’s been properly printed.